It is desirable for this laminate to be elastic in the transverse direction (that is to say in the direction extending from one flap to the other) at least, in order to allow good holding of the training pants around the waist of the baby. The current laminates are generally constituted by a film made of elastic or elastomer material which is generally sandwiched between two layers of non-woven fabric. In order to allow large-scale production of training pants, it is currently necessary to unwind this elastomer film from a reel to bring it between the two layers of non-woven fabric in order to fix them mutually, for example through lamination, for example through an adhesive. However, this method has the drawback that it is necessary to provide in the construction of the film at least one outer layer, preferably two, forming skins, which are made of a relatively inelastic material and have, amongst other things, non-adhesive or non-bonding properties which thus allows the elastomer film to be wound on itself on reels so as to unwind it easily during the production of the laminates constituted by this elastomer film and the two non-woven fabrics. The laminates known today are thus constituted by an elastic film, having at least one outer layer of a substantially inelastic material, and a sheet or layer of non-woven fabric fixed to said at least one outer layer.
This type of laminate of the prior art is complex to produce by reason of the presence of the layer(s) forming the skin(s) and also by reason of the fact that since the skin(s) is/are chosen, with regard to their material, so that they have sufficiently low bonding qualities in order to allow winding of the film, surrounded by the skins, on a reel and then easy unwinding thereof; During the fabrication of the laminate, it is necessary, in order to then stick this skin to the outer non-woven fabrics, to use so-called technical adhesives, in particular with a high tackifying power and/or with high grammage, for example greater than 12 gsm. Generally, it is necessary to carry out surface treatment such as Corona treatment or plasma torch treatment.
After formation of the laminate it is then necessary to provide for a particular mechanical treatment called “activation”, in order to allow the entire laminate constituted by the elastomer film, the skins and the non-woven fabrics to have sufficient elasticity, such as required in order to be able to adjust the waistband of training pants around the waist of a baby and to do this in spite of the relatively inelastic character of the materials chosen for the skin and the non-woven fabrics. This activation process consists in stretching the laminate transversely in the machine direction, by stretching the skin(s) and the non woven(s) beyond the elastic limit. After the stretching, the elastic film and the laminate as a whole resume a width which is greater than or equal to that before stretching, but the skins and the non woven(s) have been stretched in an irremediable manner in such a way that the laminate as a whole now has transversal elasticity, and can be stretched at least as far as the width to which the skins and the non woven(s) have been stretched irreversibly.
Laminates are also known from the prior art which are formed through direct extrusion of the elastic film on the non-woven fabric whereby the fixing is realized through hardening of the elastic material on the fibres of the non-woven fabrics. In this case also, it is necessary to realize an “activation” which does not lend itself well to non-woven fabrics which, after activation, exhibit a rough touch which tends to irritate the skin of the wearer of the training pants, particularly babies. Besides, this direct extrusion is difficult to implement and in particular the extruded elastic film in the form of a hot viscous material tends to impair the non-woven fabric to the point that fibres of the non-woven fabric fuse, rendering the surface of the non-woven fabric rigid, and are submerged in the elastic film.